Multifilar Helix Antenna Segmentation Gain Stability
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Solution Overview
Problem
Traditional all-metal quadrifilar helix antennas face challenges in maintaining isoflux radiation patterns, controlling back radiation and thermal gradients, and suppressing resonances when attempting to increase gain, which affects cross-polarization discrimination and mechanical stability.
Innovation Solution
A multifilar helix antenna design featuring three or more resonant helical elements with wave perturbations and a rotationally symmetric corrugated cover portion, which reduces resonance modes and back-radiation coupling, allowing for beam shaping and increased edge-of-coverage gain while maintaining desired radiation patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the length of the helix radiator is increased to increase gain, then the gain is improved, but the beam properties deteriorate and cross-polarization discrimination worsens
Solution Approach 1:
The helix radiator is divided into multiple helical elements (three or more) evenly distributed about an imaginary circle, with each element contributing to the overall radiation pattern. This segmentation allows the antenna to achieve higher gain through constructive interference while maintaining beam properties through coordinated phasing of the individual elements.
Solution Approach 2:
The invention transitions from a single helix to a multifilar structure by adding the azimuthal dimension, with helical elements distributed around a circle. This dimensional change enables simultaneous achievement of high gain (through array effect) and maintained beam properties (through rotational symmetry and phase control).
2Power
If the length of the helix radiator is increased to increase gain, then the gain is improved, but thermal gradients worsen
Solution Approach 1:
By dividing the radiation function across multiple helical elements, the power dissipation is distributed throughout the structure rather than concentrated in a single long element. This segmentation reduces thermal gradients while maintaining the desired gain through the collective radiation of all elements.
Solution Approach 2:
Each helical element can be optimized for local heat dissipation characteristics, and the distributed structure allows heat to be conducted down to the base through multiple paths, reducing thermal gradients along the helix radiator.
3Power
If the length of the helix radiator is increased to increase gain, then the gain is improved, but structural stability deteriorates
Solution Approach 1:
The long radiating structure is segmented into multiple helical elements that can be supported at multiple locations along their length. This segmentation improves mechanical stability by distributing structural loads and enabling intermediate support, while the elements collectively provide the desired high gain.
Solution Approach 2:
By distributing helical elements around a circular arrangement, the structure gains rotational stability and can be supported at multiple azimuthal positions. This dimensional change from a single long element to a distributed circular array inherently improves mechanical stability while achieving high gain.
4Area of stationary object
If traditional quadrifilar helix antenna is used, then compact size is achieved, but resonances increase
Solution Approach 1:
The cover portion is provided with local corrugations at specific positions to create rotational asymmetry. This local modification suppresses resonances by disrupting the symmetry that would otherwise support resonant modes, while the overall compact quadrifilar structure is maintained.
Solution Approach 2:
Rotational asymmetry is introduced through corrugations in the cover portion to break the symmetry of the quadrifilar helix structure. This asymmetry suppresses resonant modes that would otherwise be supported by the symmetric configuration, while maintaining the compact footprint of the original design.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design achieves improved isoflux radiation patterns, reduced cross-polarization, and enhanced mechanical stability, enabling increased gain without degrading beam properties or introducing thermal issues, thus addressing the limitations of traditional quadrifilar helix antennas.
Implementation Method 1
Each helical element extends in a longitudinal direction from the feed and polarizing section through the opening in the cover portion and wound to form the helix radiator
Implementation Method 2
The cover portion comprises a rotationally symmetric corrugated assembly
Implementation Method 3
The corrugated assembly... for decreasing back-radiation coupling into the feed section
Data Source
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AI summary
The invention relates to a multifilar helix antenna (1) comprising a wave feed and polarizing section (2) comprising a cover portion (3) comprising a through opening (4). The antenna (1) comprises a helix radiator (5) comprising three or more resonant helical elements (6) evenly distributed about an imaginary circle. Each helical element (6) extends in a longitudinal direction (Z) from the feed and polarizing section (2) through the opening (4) in the cover portion (3) and wound to form the helix radiator (5). Each helical element (6) comprises one or a plurality of wave perturbations (7) separated in the longitudinal direction (Z)and that each set of perturbations are positioned at the same level in the longitudinal direction (Z) to yield an equivalent array of stacked helical radiators, wherein the cover portion (3) comprises a rotationally symmetric corrugated assembly (8).